Embodiments of the present invention are directed to a biopsy needle for removal of tissue from a body for examination outside of the body.
A biopsy needle is used to obtain a sample of tissue from the body (usually from the human body, but often from the body of a non-human animal, as well) for diagnosis of disease or other examination. The sample obtained should be uniform and substantial enough to permit one to examine its structure and composition. When the sample is used for diagnosing disease, the sample should be representative of the tissue from which the sample is removed. If the sample is obtained with the proper technique and a correct instrument, it will be large and uniform enough to make diagnostically relevant findings from it.
The challenge in biopsy needle design is principally to meet two conflicting goals: 1) provide a needle that is large enough to obtain a sample of sufficient size; and 2) provide a needle that is small enough to minimize trauma to the patient. Minimizing trauma means more than minimizing pain (about which the patient cares a great deal, of course): a smaller incision in the body heals more quickly, bleeds less, minimizes infection, and reduces scarring. Current biopsy design meets these goals with varying degrees of success; many designs meet one goal but at significant expense to the other.
Biopsy needles that tend to be successful (more or less) at withdrawing large samples from a patient but with minimal trauma are almost invariably complex and expensive. They often depend on costly suction equipment and needles (as does the MAMMOTOME(copyright), for example) and/or a complex cutting mechanism. Complexity is undesirable because it increases the time required to learn to use a device, it increases the tendency of a device to fail, and it makes the device more expensive to manufacture.
There is therefore an important need in the art for a device that can remove a sufficient amount of sample with minimal trauma to a patient, and that is simple, easy to use, and inexpensive to manufacture.
It is an object of the present invention to provide a biopsy needle and biopsy needle device that can obtain a tissue sample of large size. It is a further object of the present invention that this sample is large enough so as to permit one to make diagnostically relevant findings from it. It is a still further object of the invention to provide a biopsy needle and biopsy needle device that obtains such a sample while at the same time minimizing trauma to the patient from whom the sample is obtained.
It is another object of the invention to provide a biopsy needle and biopsy needle device that is uncomplicated, that is easy to use, and that is cheaper to manufacture than are typical biopsy needles.
These and other objects are achieved by the biopsy needle and biopsy device of the invention. In a preferred embodiment of the invention, the biopsy needle comprises a hollow outer tube. At the distal end of the tube are two longer parallel edges and two shorter parallel edges that define a rectangular opening. The edges are preferably at right angles to one another, such that the longer edges are perpendicular to the short edges. The longer edges, and the shorter edge near the distal end, are sharpened to provide a razor-sharp cutting edge; the shorter edge away from the distal end is a standard edge. The hollow outer tube may be straight with the same diameter throughout or tapered towards the distal end.
In a presently preferred method of removing tissue with the biopsy needle of the invention, one inserts it into a patient""s body at a desired location and applies negative pressure via a syringe inserted at the proximal end of the needle. One then either rotates the needle or turns it back and forth. Tissue is drawn into the rectangular opening by the negative pressure, is sliced by the sharp cutting edges of the opening as the cutting edges remove tissue, and is then deposited into the lumen of the needle. As long as negative pressure is applied, tissue can be cut and deposited into the lumen throughout the cutting process.
The method and device of the invention permit one to use a needle of limited size to obtain a large amount of tissuexe2x80x94and even remove a tumor completelyxe2x80x94from a single, small insertion point. This is a significant advantage over prior art devices for diagnostic procedures, because a smaller caliber needle can be used to obtain a better tissue sample, thus minimizing potential complications and maximizing sample yield. Additionally, in certain therapeutic procedures the needle may remove the lesion completely and eliminate the need for subsequent surgical removal of tissue from the biopsy site. It moreover significantly decreases the chance that the physician performing the biopsy will miss a focus of abnormal tissue, because tissue is removed, as the needle is moved over tissue, at an increasing distance from the insertion point of the needle. This yields a larger and more representative sample of tissue for subsequent pathology evaluation, and avoids the need for multiple biopsy procedures. Limiting the number of biopsy procedures a patient must endure is a significant advantage of the invention, as it decreases both the discomfort and complications that are commonly associated with such procedures. In addition, the simplicity of the device allows one to quickly learn to use it, as well as significantly reduces its manufacturing cost.